The invention relates to a device to be incorporated in a liquid dispensing appliance for dispensing liquid in the form of foam.
Numerous applications are known in which it is desirable to dispense a liquid product in the form of a foam, for different reasons. In particular, the foam remains durably in contact with the surface to be treated by the product and the action of the foam is therefore more efficient, the distribution and spreading of the product are easier to control, contact with the skin is lighter and more pleasant in the case of toilet products, etc. Of course, the product is stored in a container in liquid form and the means which control the ejection of the liquid must then be completed by a device transforming the liquid into foam.
Such foaming devices are known and they generally comprise a liquid flow dividing member and an air intake. However, these devices, especially when they are intended for hand actuated appliances without an auxiliary driving gas, such as dispensers for soap, shampoo, household products or different cosmetics, have drawbacks. In general the liquid ejection means generate a pulsed flow, for example in the case of an alternating positive displacement pump or compression/depression of a deformable wall of a container. These known foaming devices are sensitive to such flow variations and that causes variations in the quality of the foam, depending on the stroke and the rate of operating said ejection means. Moreover, the foam is often non-existent during the first pulsations, because the device is unprimed when inoperative. Other foaming devices comprise mobile elements, such as balls or valves of various shapes, but that increases the price of the device and the risks of malfunction.
In a new way, the present invention avoids the above drawbacks.
The object of the invention is then to provide a foam forming device, mainly for a dispenser appliance whose liquid ejection means may be actuated by hand, which ensures the immediate production of foam of constant and excellent quality, while being extremely simple and economic to produce.
Another object of the invention is to provide a foaming device which can be readily incorporated directly in the liquid duct of a liquid dispenser of any known type.
A further object of the invention is a foaming device which does not require any mobile element and in which even the mobile valve of the dispensing apparatus may be omitted, if it has one, without resulting in unpriming, or leaking or dripping on the outside.